Copolymers of dichlorodifluoro-ethylene and ethylene



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PATENT OFFICE-1 me'eoe meiimimnmmenoi- I E.i1anford,.-ShortHills,-

ooro.

v iieeeiziidridj E. I. duPont de'Nemours' & Company; Wil

" .H i' r w x-I 'nineiei pdi a 27, 1947,; a S IM-182. 51,

chew: IBM- .1.

This invention relates to polymeric. in aterials tertiary butylp'eroxlde, and 35 arts .of 1.1-d1- and more particularly to polymers obtained'irom 'c hloro'. 2,2 difiuoroethylene. The reactor is dichlorodifiuoroethylenes. t v 1; 1. g {agitated and heated to170-1809C. for 8 hours This application is acontinuationein -partof during which a pressure of 750-1025 atm. is abandoned application Serial Nor-526,331.flled-5 1naintained in'the reactor by injecting water. March 13, 1944. f I I"; e At the conclusion of the reaction thefvessel is This invention has as an object 'the production cooled to r m mpemtwm and h con n s of new and useful compositions of matter. A of the tube discharged. The s olid *polymer further object is the preparation or ,valuable formed in the reaction is. filtered, washed in high molecular weight'polymers. Other objects 10. water,.and air dried at 120 C. for 25 hours. The will be apparent from the followingdescription' dried polymer amounts to 4.0 parts. This polyof the invention. .mer can bev pressed into clear films in a Car- These objects-are accomplished'bythe iollowver press. Anal. .calcd. for (CzFzClM; F, 28.6. ing invention whichcomprises polymerizing the Found: F, 29.-1.- i 1 gichlorodifiuoroethyleneas more fully described 1 Ermmplelfl ereinafter. 4 I I e v i a A silver-lined'high pressure reactor is flushed The new polymers invention which with oxygen-free hydrogen and then charged comprise both homopolymerstand copolymersrare: with 250 parts of-deoxygenated water and 0.15

obtained by reacting either of theabove men tioned. dichlorodifiuoroethylenes, namely, 1,1- i azodlcyglohexanecarbo dichloro-2,2-difiuoroethylene or 1,2.-dieh'1 ir i-1,2'- 9 i 3 M i w i e 53;? his; iiiigfi tiei i' are it? gfig and m ?h f dichloro-1,2-difluoroethy1ene: The reactor is The preferred embodiments orthe invention e5gfl fg f gi jigggfglgg g' figgg'izg f aremustratedby the following-'examples-m which maintained in the reactor by injecting Water. gg ziggg t reactants are 'VThe reaction vesselis then cooled to room temp'erature andthe contents of the tube discharged. p The solid polymer obtained from the reaction A stainless steel, highpressure reactor] is 0 after washing and drying at 60 C. under 20 flushed with oxygen-free, nitrogen andisj then mm.'vacuum f 2 110115 amounts to P charged with 250 parts of oxygen-free water t of white, lumpy 'polymerwhich can be pressed and:0.64" part of tertiary butylhydroperoxide. between Plates Of a Carver Press into a film at The-reactor is (nosedevacuated, cooled in aa-pressing temperature O C- solid carbon dioxide/methanol miXtIurQ -and 'is Example IV then further charged'with ''parts':of i ggdii, Q I chloro -2,2 difiuoroethyleherTheireactoriisz @f- A stainless steel high pressure reactor is agitated and heated to lit- 1.5.2 grorlohours flushed" with oxygen-free nitrogen and then is during which a pressure-of S'ZOQQAOatmQiS'maincharged with 25 parts of oxygen-free water and tained in the reactor by .injectingwaterg 'rhe 400.05 par Of benzoyl p Q Th v W t r 00- sum of the individual'pressure drops, during the 1 cupies about of total internal volume of the between steel plates covered wi'th aluminu n jfoilt parts of OXYE PHFQ periods between thewater repressuring 0 era,- reaction vesseLZThereactor is closed, evacuated, tions j a 0 m he e tio'n v l is cooledin a solid carbon dioxide/methanol mixcooled toroom temperaturefan'd the contents of ti re. ndiS then. further charged with 10 parts the tube discharged. 1 Thesolid polymer formed or 1, demuree Ethylene in thegreaction is filtered, iwashedl'welli .withis adm tted to th reaction. s m fr m a i h water, and air dried at.100 C .'roi-.24 hours. "The pressure stor g sy m to pr vid a l 'p' dried polymer amounts'to 6.5jparts." A film 'can -5 bQ 1@5Q a p s T reactor is be prepared by pressing the polymerati230 C. .agitatedahdheatedjto 80 C. and'the pressure inz the reactorjis:'then"raised to 500 atm.' by the -,inj eotion; of 1 an I additionalv amount or ethylene. The"teinperature fis,.. maintained at .80 C. and additional,iethylerie; isfl;'ritro'duced' to raise the bl'fi sulfe miTDQfQQtm {After/13 hours the pres- 'had*dropped to].620 "atm. The reaction Examplell V t t A stainless steel.. highjjgpressurqreactor? charged, as ijdescribed' in 'Example 5 I, wwith 1 -200 vessel is cooled to room temperature, the unreacted portion of the gaseous monomers is bled off and the contents of the reaction tube are discharged. After drying, 5 parts of a 1,1-dichloro-2,2-di.fluoroethylene/ethylene copolymer is obtained. This copolymer contains 21.72% chlorine which corresponds to a 1,1-dichloro- 2,2-difluoroethylene content of 40.7%, an ethylene content of 59.3%, and a 1,1-dichloro-2,2- difluoroethylene: ethylene mol ratio of 1:6.9. This copolymer can be pressed into continuous films which have tensile strengths as high as 1800 lbs/sq. and elongations of 600%.

Because of the extreme rapidity with which certain copolymerizations of the dichlorodifluoroethylenes proceed, particularly those containing predominant amounts of the chlorofluoroolefins of this invention, utmost caution should be exercised to avoid uncontrollable and explosive reactions, especially when operating under pressure in excess of 300 atm.

Example V A silver-lined, high pressure reactor after flushing with oxygen-free nitrogen, is charged with 200 parts of oxygen-free water and 0.15 part of lauroyl peroxide. The reactor is closed and connected to a source of a gas mixture containing 95 per cent ethylene by weight and 5 per cent 1,1-dichloro-2,2-difiuoroethylene by weight. The reactor is agitated and heated, and when the reactor reaches a temperature of 60 C., a sufiicient quantity of the gas mixture is injected to raise the pressure to 500 atm. and heating is continued. The copolymerization is carried out by injecting the gas mixture into the reactor in the pressure range of 850-1000 atmospheres at a reaction temperature of 70-75 C. during a period of hours. After cooling, the reactor is opened and 18 parts of white, lumpy copolymer are obtained. This copolymer can be pressed into clear, extremely tear-resistant and unusually limp films. For example, the Olsen stillness, as determined by A. S. T. M. test Stiffness in Flexure of Non- Rigid Plastics," D-744-43T, is 5500 lbs/sq. in., only about one-fourth that of the polymer obtained from ethylene alone. A film was too tough to tear in a test described in Technical Assoc. of the Pulp and Paper Ind., Standard Method, T-4l4-m-40, whereas the ethylene polymer is much weaker in this respect. This copolymer contains 9.0% chlorine which corresponds to a 1,1-dichloro-2,2-difluoroethylene content of 16%, an ethylene content of 84%, and

a mol ratio of 1,l-dichloro-2,2-difiuoroethylene:

ethylene of l 23.5.

Example VI In accordance with the foregoing procedure, treatment of a gas mixture containing, by weight, 96% ethylene and 4% 1,1-dichloro-2,2-difiuoroethylene with alpha, alpha'-azobis(alpha,- gamma-dimethylvaleronitrile) catalyst instead of lauroyl peroxide at 54 C. for 17.8 hours under 800-1000 atm. gives 14.5 parts of a lumpy copoly-- mer containing 4.43% chlorine. This analysis corresponds to a 1,1-dichloro-2,2-difiuoroethylenezethylene mol ratio of 1:52, or to 8.3% chlorofiuoroolefin and 91.7% ethylene by weight. The copolymer can be pressed into tough films at 170 C. in a Carver press. These pressed films have zero tenacity temperatures of 150 C., compared to 115 C. for unmodified ethylene polymer. Films also are more tear-resistant than unmodified ethylene polymer.

Example VII Desirable copolymers containing high proportions of 1,1-dichloro-2,2-difluoroethylene to ethylene can be obtained as e. g. in the following description.

A silver-lined, high pressure reactor is charged with parts of methanol and 0.2 part of alpha, alpha-azobisisobutyronitrile. The reactor is closed, cooled in a bath of carbon dioxide/methanol, evacuated, and then charged with 40 parts of 1,l-dichloro-2,2-difiuoroethylene and 50 parts of ethylene. The reactor is connected to a source of water under pressure and heated to 63-67 C., and a pressure of 850-1000 atmospheres is maintained by water injection. After 9.5 hours, the reactor is cooled and the contents discharged. The reaction mixture consists of lumpy oolyiner suspended in the aqueous methanol. The polymer is removed by filtration and dried. It weighs 35 parts. The copolymer can be pressed into clear. tough films at C. in a Carver press. Pressed films have a tensile strength of 7000 lbs./ sq. in. at 210 per cent elongation, are exceptionally tear resistant, very transparent, and rigid. The copolymer contains 42.95 per cent chlorine which corresponds to a l,l-dichloro-2,2-difiuoroethylene content of 80.7%, an ethylene content of 19.3% by weight and a mol raio of 1,1-dichloro-2,2-difiuoroethylene ethylene of 1: 1.15.

Example VIII Using essentially the same procedure as described in Example IV except that 10 parts of l,2-dichloro-l,2-difiuoroethylene is used instead of its isomer, 1,l-dichloro-2,2-difiuoroethylene, a copolymer is obtained which contains 13.1 fluorine which corresponds-to a 1,2-dichloro-l,2- difiuoroethylene content of 45.8% and an ethylene content of 54.2% by weight, or to a 1,2-dichloro-1,2-difluoroethylene:ethylene mol ratio of 1:56. Films prepared by hot-pressing the polymer between steel plates covered with aluminum foil are capable of being permanently elongated as much as 600%.

Example IX A silver-lined, high pressure reactor is charged as described in the Example V with the following: 150 parts of oxygen-free water, 0.15 part of lauroyl peroxide, 5 parts of l,2-dichloro-l,2-difiuoroethylene and 95 parts of ethylene. The reaction is carried out at 70 C. for a period of 18.6 hours under a pressure of 850-1000 atm. which is maintained by injection of water. From this reaction there is obtained 31 parts of a copolymer which contains 3.0% chlorine. This chlorine content corresponds to a 1,2-dichloro-1,2-difluoroethylene content of 5.8% by Weight and an ethylene content of 94.2% b weight. Pressed films of the copolymer have a tensile strength of 2217 lb./sq. in. at 368% elongation, an Olsen stifiness value of 45,093 lb./sq. in. and a film 6.7 mils thickness has the high tear value of 960. A film had a zero tenacity temperature value of about 137 C.

Example X A silver-lined high pressure reactor is charged as described in the preceding example with 225 parts of deoxygenated water and 0.15 part of alpha, alpha-azobisisobutyronitrile. The reactor is closed and evacuated. A liquid monomer mixture containing 59% by weight of 1,2-dichloro-1,2-difiuoroethylcne and 41% by weight of ethylene is then injected into the reactor at a temperature of 50 C. for a period of 15.6 hours, sufiicient monomer mixture being continuously injected to maintain a pressure of 450-500 atm. At the termination of the run the reactor is ,cooled, the unreacted monomer is bled oil and the tube opened. Large, lumpy, white particles of polymer suspended in water are obtained as the product of the reaction. The polymer is illtered, washed with distilled water and dried at 100 C. during five hours under a vacuum of mm. The dry polymer weighs 40.5 parts. The chlorine content of the polymer, 38.5%, corresponds to a composition containing 71% by weight of the 1,2-difluoro-'1,2-dichloroethylene and 29% by weight of ethylene. The polymer is pressed into clear, tough films at 170 C. in a Carver press. Films have a tensile strength of 6000 lb./sq. in. at 196% elongation, and an Olsen stiffness value of 192,500 lb./sq. in. A pressed film mils thick lost virtually all its tensile strength at 157 C. (i. e. the zero tenacity temperature is 157 C.) and a film 5 mils thick did not tear in a tear test described in the TAPPI test T-414m-40. A compression molded bar of the polymer had a Rockwell hardness value of 72, determined as described in ASTM-D785-44T-- Rockwell Hardness of Plastics and Electrical Insulating Materials. Films and bars are brilliantly clear, high softening and self-extinguishing in contrast to those from ethylene polymer, which are opaque, low-softening and flammable.

Example XI Into a stainless steel high pressure reactor from which the air had been displaced with oxygen-free nitrogen is charged 0.6 part of ammonium persulfate, 1.2 parts of borax, and 120 parts of deoxygenated water. The reactor is closed, evacuated and cooled in a Dry Ice-acetone bath. Into this cold reactor is introduced, successively, 50 parts of 1,1-dichloro-2,2-difluoroethylene and 100 parts of vinyl chloride. The mixture is then heated to 50 C. and maintained at this temperature under autogenous pressure, with agitation, for 12 hours. After cooling the reactor, the pressure is slowly released and the non-volatile prod- 6 a tensile strength of 7887 lb./sq. in. at 85% elongation, Olsen stifiness value of about 277,000 lb./sq. in., and a molded bar has an Izod impact value of 0.7 foot-pounds per inch of notch. Films have a zero tenacity temperature of 109 C. This polymer is more thermally stable and has a higher softening point thanpolymeric vinyl chloride.

Example XIII Vinyl fluoride parts) is copolymerized with 1,'1-dichloro-2,2-difiuoroethylene (60. parts) in accordance with the general procedure of Example III in the presence 01. 200 parts of oxygenfree water and 0.15 part of lauroyl peroxide at 68-71 C. for 11 hours under a pressure of 875-1000 atm. maintained by injection of water.

The solid polymer formed is filtered, washed Isobutylene (20 parts) and 1,1-dichloro-2,2-difluoroethylene parts) copolymerized as in the previous example in the presence of 0.15 part of benzoyl peroxide and 200 parts of deoxygenated water for 10 hours at 80-90 C. under 200-250 atmospheres give '18 parts of a white, lumpy polymer which, by chlorine analysis, has a 1,1-dichloro-2,2-difiuoroethylene:isobutylene mol ratio of 1:1.1, and .a ratio by weight of 68.3:31.7.

Example XV a).A mixture of 150 parts of oxygen-free water, 0.18 part of ammonium persulfate, 0.05

' part of sodium bisulfite, 2.0 parts of higher fatty alcohol sulfate, 1.5 parts of sodium pyrophosucts are removed. The partly coagulated dis-.

persion of polymer is stirred rapidly while aqueous saturated sodium sulfate is being added to complete the coagulation. The coagulum is ill-- tered, washed with successive portions of distilled water until the wash water gives a negative test for sulfate ion, and dried in a vacuum desiccator. The white, powdery product, ob tained in a yield of 36 parts, contains 4.4% fluorine, which'corresponds to. a 1,'1-dichloro-2,2- difluoroethylenezvinyl chloride mole ratio of 1211.7, and to a ratio by weight of 15.3:84.7.

Example XII Using a silver-lined high pressure reactor as described in previous examples, copolymerization of vinyl chloride parts) with 1,2-dichloro- 1,2-difiuoroethylene (10 parts) in the presence of 225 parts of oxygen-free water, 0.15 part 01. alpha, alpha'-azobis(alpha, gamma-dimethylgamma-methoxyvaleronitrile), and 1 part of sodium pyrophosphate for 11 hours at 30 C. under 900 atm. pressure maintained by water injection gives 43 parts of a copolymer containing 3.2% fluorine. This corresponds to 11.2% by weight of the chlorofluoroolefin and 88.8% by weight of vinyl chloride. This copolymer has a relative viscosity of 1.07 (0.1% in cyclohexanone at 25 C.) Pressed films of the copolymer have phate, and 20 parts of vinyl acetate is charged into a silver-lined high pressure reactor previously swept with oxygen-free nitrogen. The reactor is closed, evacuated, and cooled in carbon dioxide/methanol mixture, and is then further charged with 40 parts of l,2-dichloro-l,2-difiuoroethylene. The reactor is agitated and heated to C. fora period of 15.5 hours during which a pressure of 900-950 atm. is maintained in the reactor by the injection of water. The re. action vessel is then cooled to room temperature. the unreacted portion ofthe gaseous monomer is bled off and the contents of the reaction tube are discharged. The emulsion is coagulated by addition of methanol, the coagulum washed with water and dried. After drying, 37 parts of a 1,2 dichloro-1,2-difiuoroethy1ene:vinyl acetate copolymer is obtained. This copolymer contains 27.94% of chlorine which corresponds to a fluoroolefin content of 52.3%v and a vinyl acetate content of 47.7%, and to a mol ratio of 1,2-dichloro- 1,2-difiuoroethylene:vinyl acetate of 111.4. The copolymer has a relative viscosity of 0.77 (0.1 in cyclohexanone at 25C.). Films prepared by hot pressing the polymer between steel plates covered with aluminum foil have a tensile strength of 8707 lb./sq. in., an Olsen stiffness value determined according to ASTM-D747-43T-Stiffness in'Flexureof Non-Rigid Plastics," of about 2,2-difiuoroethylene and 5 parts of styrene.

495,000 lb./sq. in., and the molded bars of the copolymer have an Izod impact strength value determined according to ASTM-D256-43T-Impact Resistance of Plastics and Electrical Insulating Materials" of 0.5 foot-pounds per inch of notch. The copolymer has higher thermal stability, higher stiffness, and higher softening point than polymeric vinyl acetate.

(1)) A copolymer (15 parts) containing 70% vinyl acetate and 30% 1,2-dichloro-1,2-di'fluoroethylene is obtained by heating 7 parts of the chlorofluoroolefin, 10 parts of freshly distilled vinyl acetate, and 0.2 part benzoyl peroxide in a glass reactor at 65 C. for 16 hours under autogenous pressure. The chlorine content of this co polymer, 16%, corresponds to a l,2-dichloro-1,2- difiuoroethylenewinyl acetate mol ratio of 1:3.6.

By essentially the same procedure a mixture of parts of 1,1-dichloro-2,2-difluoroethylene, .5 parts of freshly distilled vinyl acetate and 0.1 part of benzoyl peroxide give parts of copolymer containing 26.15% chlorine, which corresponds to a 1,1-dichloro-2,2-diiiuoroethylene content of 49.1%, a vinyl acetate content of 50.9%

and to a 1,l-dichloro-2,2-difluoroethylene:vinyl acetate mol ratio of 111.6.

Example XVI (a) A mixture of 0.1 part of benzoyl peroxide, 5 parts of 1,1-dichloro-2,2-difiuoroethylene, and 5 parts of acrylonitrile is charged into a glass reaction vessel which has previously been swept with oxygen-free nitrogen. Thereactor is then evacuated and closed. After heating at 65 C. for 16 hours while agitating, there is obtained 5 parts of a copolymer of 1,1-dich1oro-2,2-difluoroethylene and acrylonitrile which contains 3.03% chlorine, corresponding to a copolymer containing 5.7% 1,1-dichloro-2,2-difluoroethylene and 94.3% acrylonitrile and to a mol ratio of 1,1-dichloro-2,2-difiuoroethylene :acrylonitrile of 1 :42.

(b) A mixture of 0.2 part of benzoyl peroxide, 8 parts of 1,2-dichloro-1,2-difluoroethy1ene, and 10 parts of acrylonitrile is polymerized using the same general procedure as described above. There is obtained 10.5 parts of a copolymer of 1,2-dichloro-1,2difluoroethylene and acrylonitrile which contains 1.64% chlorine, which corresponds to a 1,2-dichloro-1,2-difluoroethylene content of 3.0% and an acrylonitrile content of 97%, and to 2. mol ratio of l,2-dichloro-l.2-difluoroethylene :acrylonitrile of 1 :79.

Example XVII (a) Into a glass reaction vessel previously swept with oxygen-free nitrogen is charged 0.1 part of benzoyl peroxide, 5.7 parts of 1,1-dichloro- The nitrogen is removed by evacuation and the reaction vessel is closed. After heating at 65 C. for 16 hours with agitation, there is obtained 7 parts of a copolymer of 1,1-dichloro-2,2-difluoroethylene and styrene which melts and spin into continuous filaments at 90 C. The copolymer contains 17.72% chlorine which corresponds to a 1,1 dichloro 2,2 difluoroethylene content of 33.3% and a styrene content of 66.7% and to a 1,1 dichloro 2,2 difluoroethylene:styrene mol ratio of 122.57.

b) A mixture of 7 parts of 1,2-dichloro-l,2- difluoroethylene, 10 parts of styrene and 0.2 part of benzoyl peroxide. is copolymerized under the procedure described in the previous section (a) whereby there is obtained 10.6 parts of a copolymer of 1,2-dichloro-l,2-difluoroethylene and sty- 8 rene which softens and becomes tacky at C. and which melts at C. The copolymer contains 6.22% chlorine which corresponds to a mol ratio of 1,2-dichloro-1,2-difiuoroethylene :styrenc' of 1:9.7 and to a weight ratio of 11.62884 Example XVIII (a) A mixture of 0.1 part of benzoyl peroxide, 5 parts of 1,1-dichloro-2,2-difiuoroethylene, and 5 parts of methyl methacrylate is charged into a glass reaction vessel and copolymerization is carried out essentially as described in the previous example, i. e., at 65 C. for 16 hours under autogenous pressure with agitation. There is obtained 6 parts of a tough copolymer of 1,1-dichloro-2,2-difluoroethylene and methyl methacrylate which becomes soft and tacky at 145 C. This copolymer contains 4.13% chlorine which correspond to a 1,1-dichloro-2,2-difluoroethylene content of 7.8% and a methyl methacrylate content of 92.2% and to a mol ratio of 1,1-dichloro-2,2-difluoroethylene methyl methacrylate of 1 :16.

(b) A mixture of 0.2 part of benzoyl peroxide, 10 parts of 1,2-dichloro-1,2-dif1uoroethylene, and 10 parts of methyl methacrylate is charged into a glass reaction vessel and copolymerization is carried out essentially as described in the above example. There is obtained 12.5 parts of a copolymer which softens at C. and becomes tacky at C. This copolymer contains 3.03% chlorine which corresponds to a 1,2-dichloro-1,2- difiuoroethylene content of 5.7% and a methyl methacrylate content of 94.3% and to a mol ratio of 1,2-dich1oro-1,2-difiuoroethylene:methyl methacrylate of 1:22.

The products of this invention, which can contain 5 to 100% of the dichlorodifluoroethylenes. are macromolecular polymers in which the degree of polymerization is greater than three, i. e., more than three molecules of the monomers are present in the polymer.

In the preparation of the dichlorodifiuoroethylene copolymers of this invention by polymerizing a mixture of monomeric dichlorodifluoroethylene with at least one other polymerizable compound, the proportions of the latter employed, based on the total weight of monomeric ingredients, can be from about 5% to 95%. The dichlorodifluoroethylene content of the polymers of the invention can vary from 5 to 100% by weight, and although copolymers containing smaller proportions of the chlorofiuoroolefin may be obtained, 5% is, practically speaking, about the smallest amount which will effect significant modification of properties in comparison with the homop lymers of the comonomers. The most useful po mers are those containing at least 10% by weight of the dichlorodifiuoroethylene since these, in general, possess superior mechanical workability and clarity. From the standpoint of flame resistance polymers in which the major component is dichlorodifiuoroethylene are preferred.

The compounds which can be copolymerized with the dichlorodifluoroethylenes in the practice of this invention are unsaturated organic compounds which contain terminal ethylenic unsaturation and which can, per se, be polymerized to high-molecular-weight compounds. i. e., products having a degree of polymerization greater than three. Examples of such unsaturated compounds comprise the vinylidene compounds which include both the vinyl and vinylidene compounds such as vinyl esters, e. g., vinyl acetate, vinyl prothe homopolymers of these hydrocarbons more flexible and less brittle than the vinyliolene pionate, vinyl stearate, vinyl trimethylacetate, 'applieations'in wliim theiunplasticiized vinylidene I vinyl and vinylidene halides of which vinyl chlohalide homopolymers cannot be employed. j

ride, vinyl fluoride, vinylidene chloride ,and vin- -.Copolymers of;1the] dichlorodifluoroethylenes ylidene fluoride are the most useful. Further with vinyl esters,fsuch aslv1nyl acetateand vinyl examples of the vinylidene and other polymer-r 5- trimethy1aoetate, [arejoutstanding in comparison izable compounds containing terminal ethylenic with thehomopolymers' of these vinyl esters in unsaturation are the acrylic and methacrylic' being. much higher softening ,andil 'much .less acids and their derivatives such as the esters of sensitive to" moisture, For example, polyvinyl lower aliphatic alcohols, e. g., methyl, ethyl, etc., acetate is so low softening as 'to be virtually the anhydrides, amides, and nitriles; olefinic hy- 10, useless in plastics applications, whereas its codrocarbons, e. g., monoolefinic hydrocarbons such polymers" with dichlorodifiuoroethylenes soften as ethylene, styrene, propylene, isobutylene; diwell aboveroom temperature. Moreover, polyenes such as butadiene, chloroprene, fiuoroprene, vinylJ'acetate, often employed as an adhesive, isoprene; tetrafluoroethylene and trifiuorochlorohas the-serious disadvantage of losing much of ethylene. Of these polymerizable i'insaturated its strength. on exposure to'water, whereas coorganic compounds containing terminal ethylenic polymers ofvinyl acetate with the. dichlorodiunsaturation, those vinylidene compounds in fluoroethylenes lose virtuallyv none of their tenwhich the terminal ethylenic carbon atom is sile strength after soaking 24 hours in water.

attached solely to..hydrogen are preferred be-' 'Copolymers ofwthe dichlorodifluoroethylenes cause they copolymerize most readily with the with completely halogenated fiuorool'efins, such dichlorodifiuoroethylenes of this invention. as tetrafluoroethylenahave the important ad- -The properties of the dichlorodifluoroethylene vantages over vpolytetrafluoroethylene itself in copolymers of this invention vary considerably being more 'readily moldable and in-being exwith the comonomer employed, ranging from itrudablerx Thus, these. copolymers have essene limp, flexible, translucent materialsto extremely 25 tially the same'superb chemicaland-heat statough, rigid, transparent solids; In general, they bility as polytetrafluoroethylene' combined. with differ from the homopolym'ersof both of. the markedly.improvedjfmechanical. workability.

dichlorodifluoroethylenes andpof the other [co-C The catalyst should be employed" in an amount 1 monomers in exhibiting abnormally high stiffin excess of 0.00l%.1(based on thet'otal weight ness, impact strength, tear resistance in thin war mb' omer'sTfnflg aL than 0f film form, and tensile strength. These copolya catalyst will beiusedthe preferred amount being mers also differ from the homopolymers of the 7 between 0.1 and 1.0%. v Q comonomers with respect to increased zero tenac The polymerization can be effectedin bulk; ity temperature, flame resistance, moisture senin solution, e. 'g., in tertiary butanol, methanol,

sitivity, and, in many cases, improved transor benzene; or in emulsion byapplication of heat, parency. These last named properties are, of light, oxygen, or polymerization catalysts. ,For course, exhibited to the highest degree in the ve u s p m o e ecan be emp oyed homopolymers of, the dichlorodifiuoroethylenes. Surface-active 'agents, g -j. eC-higher alkyl Dichlorodifluoroethylene/ethylene copolymers betaines such as c cetyl e ine, the qu rn ry are outstanding in manyrespects in comparison 40ammonium halides such as cetyltl yl with ethylene polymen Those copolymers con monium chloride; and the alkali metal and amine training from about 10% to about 40% dichlorosalts of higher alkanol sulfates such as the sodifluoroethylene by weight are considerablyless j dium or diethylcyclohexylammonium dodecyl stifl. than ethylene polymer, a propertynwhich isv sulfates. The polymerization can be effected as desired in many unsupported film uses. qfnf gen-y a batch, semi-continuous, or continuous process.

eral, these copolymers also have higher tensile 'A wide variety of polymerization catalysts can strength than ethylene polymer and',fin' thin secbe employed in the practice of this invention. tions, markedly improved tear resistance. Their Among the most useful are the peroxygen'and durability on outdoor exposure is also significant azo compounds. By peroxygen compounds is ly better than that of ethylene polymer. Di- 5U meant a compound-containing the peroxy en chlorodifluoroethylene/ethylene copolymers conlinkage, -OO,Zandby azo compounds is taining about 40% dichlorodifluoroethylene by meant a compound containing'the azo" linkage, weight, on the other hand, tend to soften higher -N=N'. Suitable peroxy' catalysts comprise than ethylene polymer and, to be stifier than it, diacyl peroxides, e. g., ,benzoyl peroxide and the stiffness increasing with the dichlorodifiuoro lauroyl peroxide; .diethyl peroxide, tertiary butyl ethylene content. In contrast to ethylene poly I hydroperoxide and hydrogen peroxide, barium mer, these copolymers are transparent andare fperoxide, magnesium peroxide, ammonium perself -extinguishing; 1 senate, sodiurn persulfate. potassium persulfate,

copolymers of the dichlorodifiuoroethylenes and. the like EXampIesof a zdoomp ounds, aside with other olymerizable monoolefinic hydrocar' so I from thoseiillustrated .in the: examples, useful bons, such as styrene, and isobutylene,i d' f ilar respects. Among outstanding diffre' g noted improved softening point, impact strength and stiffness. 1, copolymers of the dichlorod'ifluoroethylenes with vinylidene halides, such' asflvinyl chloridep j vinyl fluoride, vinylidene chlorideand vinylidene rate, f 1,1 azodicyclohex'anecarbonitrile, alpha,-

,jchlorodifiuoroethyle'nes. described herein 1 can; be

"infth iqpractice,of the invlention ,includealphaw i :alphaT-azobi'si -(alphamethylbutyronitrile)g" dimethyl and; diethyl "1-;alpha',alpha'-azodiisobutye .z d s bei r erbe emideiel h alphe azobisialphafphenylpropionitrile)', etc. In gen- .eralgthe synthesis-of. homopolymers ofthe di- 1 fluoride, are. noted for their iimprovedthermal effected;withlthegsaniecatalyst,'but higherpres- I, stability and mechanical workability =in compari- 701sures oi" longer l -reaction:periodsare usually ire-- son with the homopolymers of these vinylidene,

. r dr r o e mer e m an or the c halides. In general, these copolymers'tend tofbe .mne: p'qiyme eu n a xes are generallyapp halide homopolymers. These 'propertiesfrnakei cable are withinthe range of aboutl v I the copolymers d eblewi venness '1 eeni -a1 r we- .2 e ee msee the type of catalyst used. With diacyl peroxide catalysts, temperatures ranging from 60-120 (1.; with persulfate or azo catalysts, 20-100 0.; and with dialkyl peroxides, IOU-150 C. are generally used. The pressures used will range from 1 to 1000 atm. or more, the-maximum pressure being' limited only by the apparatus available.

The products of this invention are adapted to a variety of uses. They may be used in molding plastics, films, foils, fibers, and adhesives. They are especially useful, particularly the ethylene/- dichlorodifiuoroethylene copolymers, as safety glass interlayers. Fibers and films oi the polymers of this invention can be used as insulating materials by wrapping the article to be insulated. These wrappings can be set by heat treatment to eliminate the tendency of the insulation to unwrap. This heat setting treatment, particularly of oriented fibers and films, results in an increase in their flexible life, i. e., the resistance to heat embrittlement. Solutions of the polymers can be used for coating wires, coils, fiber glass, bentonite films, porous carbon articles, ceramics and mica. Dispersions of the polymers can readily be prepared, for example,

from solutions of the polymers. For many of these purposes, the polymers may be combined with or prepared in the presence of plasticizers, stabilizers, fillers, pigments, dyes, softeners, natural resins, or other synthetic resins.

As many widely difierent embodiments of this invention may be made without departing from the scope and spirit thereof, it is to be understood that this invention is not limited to the specific embodiment thereof except as defined in the ap-. pended claims.

I claim:

1. A macromolecular copolymer of a dichloro- REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,388,178 Peterson Oct. 30, 1945 2,393,967 Brubaker Feb. 5, 1946 2,407,419 Hanford Sept. 10, 1946 2,419,009 Cofiman Apr. 15, 1947 FOREIGN PATENTS Number Country Date 110,457 Australia May 9, 1940 796,026 France Mar. 27, 1936 OTHER REFERENCES Locke et al., J. Am. Chem. Soc., vol. 56, pp. 1726-1728, 1934.

McBee et al., Abstract of Papers 112-The Meeting of the American Chem. Soc. 1947, page 14J.

McBee et al., Ind. & Eng. Chem. vol 41, No. 1, 1949 pages 70-72. 

1. A MACROMOLECULAR COPOLYMER OF A DICHLORODIFLUORTHEYLENE AND ETHYLENE WHICH COPOLYMER CONSIST OF, BY WEIGHT, ABOUT 5% TO 81% OF SAID DICHLORODIFLUOROETHYLENE. 